Why the power spectral density(PSD) of BMI088 Gyro(x/y/z) have strange peak point?

[Silva]

I sample the BMI088 sensor static data in the marble platform in 0.5 hour,  then calc the gyro(x/y/z) PSD, and found the strange peak point on x/y/z as the image below, what is the root cause?  btw, BMI088 acc PSD is normal.

bmi088 gyro PSD peak point issue(abnormal)

more test detail below for reference:

1.  BMI088 settings:   23Hz LPF， 200Hz.

2.  BMI160 settings and gyro PSD(normal,  for reference).

74.6 Hz LPF， 200Hz

BMI160 gyro PSD is normal

[FAE_CA1]

Hi Silva,

If your MCU timer interrupt has precise 10ms interval for example for 100Hz sampling rate, then you can set BMI088 gyro to 200Hz ODR/23Hz BW. When timer interrupt happens you can read gyro 6 byte data registers in one SPI or I2C transaction as burst read. Then you can plot your gyro data for standard deviation or PSD.

Thanks.

[FAE_CA1]

Hi dxglaw,

Thanks for your inquiry.

BMI088 gyro is the same as BMG160 at https://www.mouser.com/datasheet/2/783/BST-BMG160-DS000-09-1221199.pdf. Please refer to page 44 that shows 523Hz BW at 2000Hz ODR is unfiltered data. However, when BMI088 is stationary the x/y/z raw data still should be within typical +/-1dps or +/-3dps min/max. It should not go to +/-15dps range like your plot. Maybe the noise comes from your PCB soldering. Please try our BMI088 shuttle board for testing.

Thanks.

[dxglaw]

Hi FAE_CA1,

Thank you for your explanation.

I will try Bosch's shuttle board to see if the noise is better. Before that, I have two questions.

1. Is the typical +/-1dps or +/-3dps min/max for 2000dps gyro range? I am using 2000dps gyro range.

2. I have a BMI055 shuttle board. Can I use that?

Could you also help me to understand the strange spikes in the PSD of the filtered (230)Hz gyro data?

Thanks again.

[Silva]

Hi FAE_CA1,

As you mentioned that 'BMI088 gyro has typical noise density of 0.014dps/rt(Hz)',  Please confirm that if the gyro noise level is correlative with gyro range, the bigger range ,the larger noise level?  if so, which gyro range with the typical noise density of 0.014dps/rt(Hz).

thanks.

[FAE_CA1]

Hi dxglaw,

The gyro zero rate level or offset is not related to the full scale range. This means that the typical +/-1dps and min/max of +/-3dps apply to all full scale ranges.

Yes, you can use BMI055 shuttle board for testing because the gyro part is the same in both BMI055 and BMI088.

Please share the gyro raw data when you plot the PSD at 2000Hz ODR/230Hz BW.

Thanks.